The present application is related to vehicle measurement or inspection systems configured to acquire measurement data associated with components of a vehicle as the vehicle moves through a vehicle inspection lane, and in particular, to a vehicle measurement or inspection system in which measurement data acquired from a moving vehicle is compensated for at least one variable associated with the motion of the vehicle, to facilitating comparison with measurement data or specification values associated with the vehicle in a stationary condition.
Systems for measuring or inspecting vehicle properties, such as wheel alignment and associated parameters, are traditionally set up for obtaining measurements to a high degree of accuracy under controlled conditions, such as with a vehicle disposed on a level surface or alignment lift rack in a stationary and driverless configuration. These vehicle measurement or inspection systems may require the temporary placement of various inclinometers or optical targets on the vehicle wheels, from which data is acquired to determine the various measurements.
Vehicle wheel alignment systems have utilized a variety of techniques for non-contact measurement of stationary vehicle wheel assembly parameters, from which vehicle wheel alignment angles can be determined. For example, by utilizing multiple displacement measurement sensors, displacement measurements between known sensor locations and multiple locations on a stationary vehicle wheel assembly can be measured. Processing the acquired measurements from sensors observing wheels on opposite sides of an axle can identify planes parallel to the wheel assembly surfaces, from which representations of axle total toe and wheel camber angles for the vehicle can be determined. In other configurations, two-dimensional images of a stationary vehicle wheel assembly are acquired, and image processing algorithms utilized to identify geometric features such as the wheel rim edge, from which a perspective analysis can be performed to determine estimates of vehicle wheel assembly spatial position and orientation. Alternatively, structured light patterns, such as multiple laser lines, or colored stripes, can be projected onto the stationary wheel assembly surface and observed by an imaging system. Deviations in the projected pattern are analyzed to generate representations of the illuminated surfaces, from which vehicle wheel assembly spatial position and orientation can be estimated. In general, these systems require the vehicle to remain stationary relative to the sensors during the measurement acquisition procedure, but some non-contact measurement systems require either the wheel assembly or the sensors be rotated in place about a stationary axis of rotation during the measurement acquisition procedure.
Some non-contact measurement systems can acquire measurements as a vehicle wheel assembly is both rotated and translated past the sensors, i.e., as the vehicle is moving or driven between a set of sensors. For example, using laser displacement sensors to measure a distance between a fixed sensor and various points on vehicle wheel assemblies on opposite sides of a vehicle as a vehicle is driven between the sensors, enables a vehicle inspection system to acquire measurement data along horizontal slices of the wheel assemblies, from which approximations of the wheel and axle spatial orientations can be derived. These types of systems are highly influenced by the speed at which the vehicle travels between the sensors, the angle (straightness) of vehicle traveling relative to the sensor observation axis, suspension movement, the presence and weight of the driver, and changes in a steering direction of the vehicle as it passes between the sensors. Measurements acquired from a moving vehicle are useful to provide a vehicle service quick check or audit inspection, capable of identifying vehicles which may be in need of a further, more precise, alignment inspection and/or adjustment.
Accordingly, there would be a benefit to the vehicle service quick check or inspection industry if additional vehicle measurements are acquired as the vehicle is driven, such as by a customer, through a measurement region of a vehicle inspection lane without stopping, and if variations in vehicle speed, steering, suspension movement, driver presence, or direction of travel are identified and/or accounted for during the acquisition of measurements associated with the moving vehicle, enabling resulting measurements of the vehicle in motion to provide meaningful information relative to specifications or measurements associated with a stationary vehicle.